Miniature diaphragm relay



July 1 6 H. s. WOODHEAD MINIATURE DIAPHRAGM RELAY Filed Oct. 19, 1965 United States Patent 3,331,040 MINIATURE DIAPHRAGM RELAY Harry Stanley Woodhead, Harlow, England, assignor to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Oct. 19, 1965, Ser. No. 497,945 Claims priority, application Great Britain, Mar. 12, 1965, 10,571/ 65 13 Claims. (Cl. 335151) This invention relates to electromagnetic contact-making relays and particularly to relays employing annular contactswhich may be closed by a resilient diaphragm.

According to the invention such a relay includes an outer magnetic member, an inner magnetic member passing through an aperture in the outer magnetic member and electrically and magnetically insulated therefrom, and a resilient diaphragm of magnetic material secured at its periphery to the outer magnetic member and normally spaced from the inner magnetic member, the diaphragm and the inner magnetic member constituting the contacts of the relay and being capable of being brought into contact with each other by the energization of a magnetic circuit that includes the said two magnetic members and the diaphragm.

Other features of the invention will be evident from the following description of a preferred form of electromagnetic. relay embodying the invention. The description refers to the accompanying drawing in which:

FIG. 1 shows a longitudinal section of the relay along its center line, and

FIG. 2 shows a cross-section of the relay in the plane marked II-II in FIG. 1.

The relay shown in the drawing is built up upon a composite seal assembly comprising a mild steel annulus having a nickel-iron tube 11 secured within its central aperture by an annular seal 12, for example of glass. The annulus 10 and tube 11 form part of the magnetic circuit of the relay, and the annular end face 13 of the tube 11 also form one of the two cooperating contacts of the relay. The armature and the other contact of the relay are formed by a resilient diaphragm 14 of magnetic material which is secured at its periphery to the mild steel annulus 10 by means of a closure member or end cap 15 which is itself sealed around its periphery to the annulus 10. A spacing ring 16 ensured that when the diaphragm 14 is in the unstressed state a suitable isolating gap remains between the central contact-making area of the diaphragm and the cooperating end face 13 of the tube 11; the correct spacing of the diaphragm may alternatively be obtained by suitably profiling the end face of the annulus 10.

It will be seen that the contact pair formed by the diaphragm 14 and the end face 13 of the central tube 11 are contained in a sealed enclosure, and that the major sealing operation involved in making the enclosure, the sealing of the tube 11 within the annulus 10*, can be performed as the first manufacturing step in the construction of the relay so that the relatively high sealing temperature required cannot efiect items such as the diaphragm 14 or the relay winding which are added to the assembly at a later stage. The end cap 15 can be secured to the annulus 10 by low temperature soft soldering.

The diaphragm 14 is provided with a number of slots 17, of length much greater than their width, that serve to increase the resiliency of the diaphragm and thus to reduce the stress necessary to distort it to make contact with the cooperating contact surface 13. The slots 17 are in the form of arcs of circles and are so interconnected that the central contact-making area 18 of the diaphragm is connected with its peripheral area 19, by which it is secured to the annulus 10 by three tongues of metal 20, of width small relative to their length. This arrangement allows the central area of the diaphragm considerable freedom of movement while at the same time ensuring that when it is attracted to the tube 11 by enerization of the associated magnetic circuit it moves substantially normally into contact with the end face of the tube.

The diaphragm 14 must, of course, be made of a magnetic material such as a nickel-iron alloy, and in order to provide a good electrical contact it may be plated over all or part of its area with a suitable noble metal such as palladium. A similar layer may be plated 'on to the end face 13 of the tube 11. Besides forming the contact surface the protective layer or layers also provide the necessary magnetic insulating spacer between the contact members.

The tube 11 forming the inner magnetic member of the assembly is considerably longer in the axial direction than the corresponding outer magnetic member formed by the annulus 10, the projecting part of the tube being surrounded by the operating Winding 21 of the relay which is wound on an insulating former 22. The outside diameter of the winding 21 and the former 22 is made not greater than the outside diameter of the annulus 10. An end plate 23 of magnetic material is secured by crimping to the end of the tube 11 projecting from the winding former 22, so as to hold the latter in position. The magnetic circuit is completed by an outer cover 24 of magnetic material which is sprung into position over the annulus 10" and the end plate 23; the cover is insulated from the end plate by an insulating washer 25 to avoid electrically short-circuiting the relay contacts.

It will be seen that the tube 11 is sealed off at the end 26 remote from the contact assembly. The sealingolf of the tube may be performed at any stage during the manufacturing process; for example the open tube may be used to allow the contact chamber to be evacuated or filled with a suitable inert gas, as the final manufacturing operation immediately before sealing the tube.

The terminals of the relay consist of contact pins projecting from the curved face of the relay assembly. The spacing of the pins may be such as to comply with the normal track spacing for printed circuit assemblies, the small physical dimensions of the relay (a practical realization of the arrangement shown in the drawing being approximately 0. 6 inch long and 0.4 inch in diameter) rendering it particularly suitable for such applications. The coil terminals of the relay are formed by pins 27 projecting from the coil former 22, while the contact terminals are formed by pins 28 and 29 respectively projecting from the outer annulus 10' of the seal assembly and from the end plate 23.

It is to be understood that the foregoing description of specific examples of this invention is not to be considered as a limitation on the scope.

What is claimed is:

1. An electromagnetic contact-making relay including an outer magnetic member, an inner magnetic member passing through an aperture in the outer magnetic member and electrically and magnetically insulated therefrom, and a resilient diaphragm of magnetic material secured at its periphery to the outer magnetic member and having a distinct contact area normally spaced from the inner magnetic member, said inner magnetic member being formed as a tube having an open end, the diaphragm and the open end of the inner magnetic member constituting the contacts of the relay and being capable of being brought into contact with each other by the energization of a magnetic circuit that includes the said two magnetic members and the diaphragm.

2. A relay according to claim 1 wherein the diaphragm has therein two or more apertures in the form of arcuate slots situated between its peripheral and contact-making areas and so formed that their presence reduces the stress necessary to cause the diaphragm to make contact with the inner magnetic member.

3. A relay according to claim 2 wherein the said apertures are slots of width small relative to their length.

4. A relay according to claim 2 wherein the said apertures are so formed that the contact making area of the diaphragm is connected with its peripheral area by two or more tongues of width small relative to their length.

5. A relay according to claim 4 wherein at least the contact making area of the diaphragm has thereon a layer of a noble metal.

6. A relay according to claim 4 wherein the surface of the inner magnetic member that cooperates with the diaphragm has thereon a layer of a noble metal.

7. A relay according to claim 2 wherein the inner magnetic member is connected with the outer magnetic member by an impervious seal.

8. A relay according to claim 7 wherein the diaphragm is contained in a sealed enclosure formed in part by a closure member sealed at its periphery to the outer magnetic member.

9. A relay according to claim 1 wherein the inner mag netic member extends beyond the outer magnetic member on one side thereof and is surrounded by an operating winding of the relay.

10. An electromagnetic contact-making relay including an outer magnetic member, an inner magnetic member passing through an aperture in the outer magnetic member and electrically and magnetically insulated therefrom, said inner magnetic member extending beyond the outer magnetic member on one side thereof and being surrounded by an operating winding of the relay, and a resilient diaphragm of magnetic material secured at its periphery to the outer magnetic member and normally spaced from the inner magnetic member, the diaphragm and the inner magnetic member constituting the contacts of the relay and being capable of being brought into contact with each other by the enerization of a magnetic circuit that includes the said two magnetic members and the diaphragm, an end plate of magnetic material on the side of the operating winding remote from the outer magnetic member and a cover of magnetic material joining the end plate and the outer magnetic member and at least partly enclosing the winding, the end plate and cover forming a magnetically conductive but electrically insulating path between the outer magnetic member and the remote end of the inner magnetic member.

11. A relay according to claim 10 wherein the contact making surface of the inner magnetic member has the form of a plane annulus.

12. A relay according to claim 10 wherein the inner magnetic member is a tube Whose end face forms the contact surface that cooperates with the diaphragm.

13. A relay according to claim 12 wherein the said tube is closed at the end remote from the diaphragm.

References Cited UNITED STATES PATENTS 1,932,164 10/1933 Petit 20087 2,798,130 7/1957 COX 20083 2,812,406 11/1957 Egan 200166 2,933,571 4/1960 Howell 200l44 3,118,988 l/l964 Nitsch 20087 BERNARD A. GILHEANY, Primary Examiner.

J. I. BAKER, R. N. ENVALL, JR., Assistant Examiners. 

1. AN ELECTROMAGNETIC CONTACT-MAKING RELAY INCLUDING AN OUTER MAGNETIC MEMBER, AN INNER MAGNETIC MEMBER PASSING THROUGH AN APERTURE IN THE OUTER MAGNETIC MEMBER AND ELECTRICALLY AND MAGNETICALLY INSULATING THEREFROM, AND A RESILIENT DIAPHRAGM OF MAGNETIC MATERIAL SECURED AT ITS PERIPHERY TO THE OUTER MAGNETIC MEMBER AND HAVING A DISTINCT CONTACT AREA NORMALLY SPACED FROM THE INNER MAGNETIC MEMBER, SAID INNER MAGNETIC MEMBER BEING FORMED AS A TUBE HAVING AN OPEN END, THE DIAPHRAGM AND THE OPEN END OF THE INNER MAGNETIC MEMBER CONSTITUTING THE CONTACTS OF THE RELAY AND BEING CAPABLE OF BEING BROUGHT INTO CONTACT WITH EACH OTHER BY THE ENERGIZATION OF A MAGNETIC CIRCUIT THAT INCLUDES THE SAID TWO MAGNETIC MEMBERS AND THE DIAPHRAGM. 